DOCUMENTED PROOF WAS PROVIDED, WHAT MORE MUST I DO

After weeks of personal contact with Nestlife Assurance where documented proof was furnished for duplication of payment we are still being told that the onus is on my mother to prove that there is a duplication. Two reference numbers (56928 & 17593) are provided detailing payment to (via Ethekwini municipality) but Nestlife can only account for one and the other payment is in Limbo. The buck keeps getting passed.and the refund becomes more elusive.